"There are some phones that are not supported by any tools,"
said Kevin Mansell, a hi-tech crime trainer for Centrex, the police
training authority. Amongst other disciplines, Mansell trains
officers in retrieving data from mobile phones.
"But it's important to remember that data on phones can always
be retrieved manually, just as you would navigate through
your own phone," Mansell told OUT-LAW.
The claim that some models of mobile phone are impenetrable to
police forensic searches came from a Cambridge University
researcher. Tyler Moore, a PhD student in computer security at
Cambridge, analysed the way that police forces conduct digital
forensics. He found that a lack of phone operating system standards
means that forces do not always have the right tool to penetrate a
phone.
"Uncommon phone types are often inaccessible with standard
software products," he told OUT-LAW. "This is an undesirable
outcome for law enforcement, and it is a direct consequence of
mobile phone manufacturers' choosing to store data in proprietary
formats rather than standard ones."
Retrieving data from mobile phones has become a vital part of
police work, said Mansell. "Law enforcement is examining mobile
phones every single day. Think how much you use your phone, how
long you've had it," he said. "The longer you have it the more it
becomes a fingerprint of the way you live your life. That is of
interest if you are a suspect, a victim or a witness in a
case."
Moore chose to examine the differences between forensics for
computers and for mobile phones. Computers store information in
standardised formats, making data relatively easy to retrieve. The
fact that mobile phone manufacturers write their own operating
systems has serious implications for policing, he argues.
"The main point of my paper is to introduce principles from
economics to digital forensics," said Moore. "Most law enforcement
agencies face very real budget constraints, so they are sensitive
to the costs of extracting data from digital devices for forensic
examination."
"The cost of extracting data on mobile phones is higher, since
software has to be individually developed for each manufacturer and
tailored to individual models," said Moore.
"Some tools work with 200 phones, but when you think that a
phone that comes in for examination could come from any
manufacturer and be from the last 10 to 15 years, you see that 200
is only a fraction of the total," said Mansell.
The sheer number of phones to be examined in cases poses a
challenge for the police. "Volume is an issue, but one that can be
dealt with by resourcing and hopefully with new and better forensic
tools," said Mansell.
Mansell pointed out that time-consuming manual examination can
still retrieve phone data. There does not, though, appear to be an
easy solution to retrieving deleted data on a phone for which there
is no examination software.
Though mobile phone networks keep some data, it is often not as
detailed as the police would like. "Law enforcement would like them
to keep everything and forever," said Mansell. "In reality it ends
up being a compromise."
